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In this paper, Bi2212 films were prepared on LaAlO 3 (100) and SrTiO 3 (100) substrates by the sol-gel method using Bi(NO 3) 3 ·5H 2 O, Sr(NO 3) 2 , Ca(NO 3) 2 ·4H 2 O and Cu(NO 3) 2 ·3H 2 O as raw materials. TritonX-100 (TX-100), fatty alcohol poly oxyethylene ether (AEO-9), poly (vinylpyrrolidone) (PVP) and poly (vinyl alcohol) (PVA) were used as surfactants, respectively, to improve the wettability between the sol and the substrate. When glycine and glycolic acid were used as complexing agents, these surfactants were stably miscible with the sols. The effects of different surfactant sol-gel systems on the wettability of substrates as well as the crystallinity, morphology, surface roughness and electrical transport properties of Bi2212 superconducting films were investigated. The results showed that flat and continuous c -axis epitaxial Bi2212 films were obtained using all these sol-gel systems. In particular, TX-100 and AEO-9 as surfactants showed stronger wettability of the sol-gel for both substrates. In addition, the films prepared using polymer surfactants PVP and PVA sol-gel systems showed less surface roughness. The same patterns were found in all the film samples prepared using precursor sols of different complexing agents, and all the films exhibited good electrical transport properties. This work lays a certain research foundation for the preparation of thin films by aqueous solvent sol-gel method. The method also shows great potential in terms of the stability of different sol-gel systems and the improvement of the wettability of different substrates. [ABSTRACT FROM AUTHOR]

The complexed sol-gel method has unique advantages in the preparation of multi-component functional thin films. In this paper, Bi2212 superconducting thin films were prepared by sol-gel method on SrTiO 3 (100) single crystal substrates. Glycine and glycolic acid were used as complexing agents. The thermal decomposition processes of the two sols were analyzed by contrasting thermal-thermogravimetric curves. The heat treatment processes of the different complexing agent systems were optimized to obtain films with flatter surface morphology. The phase composition of the intermediate products during the precursor heat treatment was changed by adjusting the conditions of the complexing agent and the acidity of the sol, which expanded the pure phase temperature interval of the final product. The pure phase temperature interval, morphology, surface roughness, and electrical transport properties of Bi2212 superconducting films prepared with different complexing agent sol-gel systems were investigated. When glycolic acid was used as the complexing agent, the Bi-2212 superconducting films showed the widest phase formation temperature zones of 25 K. They also had a smaller surface roughness of 10–15 nm. Other than that, all samples had good epitaxial properties, and electrical transport properties. This work provides a new idea for expanding the phase-forming temperature region of multicomponent functional ceramics. It also shows the promising potential of sol-gel method for preparing multicomponent functional films with high quality surfaces. [ABSTRACT FROM AUTHOR]

Lead-free ceramics have attracted considerable research attention owing to their environmentally friendly properties as well as their relatively good piezoelectric properties. Herein, we doped BiCoO 3 (BCO) onto (Bi 0.5 Na 0.5)TiO 3 –6BaTiO 3 (BNT-6BT) solid solution at various concentrations and investigated their dielectric and piezoelectric properties. After comparing the Rietveld refinement data with X-ray diffraction (XRD) results, it was found that all the BNT-6BT- x BCO ceramics (x = 0, 0.5%, 1%, and 1.5%) showed the morphotropic phase boundary conformation with coexisting tetragonal (P4bm) and cubic (Pm 3 (＿) m) phases. XRD refinement data also demonstrated that with increasing BCO concentration to 1.5%, the mole ratio between the tetragonal and cubic phases was close to 1:1, which enhanced the piezoelectric performance of the ceramic composites. At a BCO concentration of 1.5%, the strain and piezoelectric coefficient (d 33) of the sample reached 0.31% and 196 pC/N, respectively. The highest effective d 33 * of 489 pm/V was obtained at 110 °C with BNT-6BT-1.5BCO ceramics. The BNT-6BT-xBCO ceramics show great promise for use in high-temperature actuator applications. [ABSTRACT FROM AUTHOR]

W–Re alloys find wide application in high-temperature measurements and as components of engines and aircraft. However, their low oxidation and thermal shock resistances have limited their application at high temperatures in oxidized atmospheres. In this work, an inner WSi 2 coating was first prepared on the surface of the W-26Re alloy by pack cementation. Subsequently, an outer ZrB 2 -HfO 2 -SiC (ZHS) coating was prepared by the sol-gel method and blade coating, using self-prepared nano-HfO 2 fibers introduced in different ratios (0%, 3%, 6%, and 9%). Following thermal shock tests at 1073–1773 K, the coatings toughened by nano-HfO 2 fibers with high melting point (above 3000 K) showed better thermal shock resistance, especially the 6% HfO 2 -doped coatings. The 6%Hf-ZHS coating underwent the highest number of thermal shock cycles (369), 385.5% and 210.1% higher than those experienced by W-26Re and ZHS. In addition, the thermal shock resistance of ZHS was 56.6% better than of the bare W-26Re alloy. Finally, the protection mechanism of the above coatings was explained by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction analyses. [ABSTRACT FROM AUTHOR]

Antiferroelectric film capacitors have attracted increasing attention due to their excellent energy storage properties. In this work, PbZrO 3 (PZO) antiferroelectric films have been prepared on the flexible fluorphlogopite (Mica) and rigid Pt/Ti/SiO 2 /Si substrates with a seed layer of LaNiO 3 (LNO) layer by sol-gel process. The microstructure and energy storage properties of the films have been systematically studied. The results show that the Mica-Pt-LNO-PZO (M -LNO-PZO) thin film has an improved energy storage density (W rec) of 16.6 J/cm3 with a charge and discharge efficiency (η) of 50.4%. Furthermore, the flexible thin films exhibit good stability under a wide working temperature range of 25–140 °C and an electric fatigue endurance of 107 cycles. Besides, the capacitive films can endure a bending radius of 4 mm and 104 bending cycles (@ r = 4 mm) with almost unchanged in the energy storage properties. The excellent energy storage properties endow inorganic thin films with great potential in flexible electronic devices. [ABSTRACT FROM AUTHOR]

Pt-loaded curling-like Bi 2 WO 6 (BWO) microdiscs were fabricated via a simple one-step hydrothermal and impregnation route. Various characterization methods, such as XRD, EDS and TEM, were conducted to prove the successful Pt loading. Electron migration from the semiconductor BWO to the precious metal Pt was revealed by the blue shift of the Bi 4f and W 4f XPS peaks with the increase of the Pt loading amount and the ∼10-fold baseline resistance elevation of the BWO-based sensor by the Pt loading, proving the formation of Schottky junction. Among the pristine BWO and Pt-loaded BWO with different Pt loading amounts, 1 wt % Pt-loaded BWO exhibits the highest gas response of 209 in sensing 500 ppm triethylamine at 300 °C, a minimal selectivity coefficient of 130.6 against some typical interfering gases at the same concentration and a low detection threshold of 1 ppm. Additionally, the sensitization mechanism is discussed as the synergistic effect of noble metal catalytic effect and metal-semiconductor junctions. [Display omitted] [ABSTRACT FROM AUTHOR]

Bi ions-doped materials have attracted increasing attention because of their potential applications in LED light sources and imaging displays. However, the correlation between local glass network structure and visible emission of Bi ions is rarely discussed, which hinders the optimization of Bi ions-doped glass. In this work, we prepared the Bi ions-doped borosilicate glasses (Bi-Glass) with tunable visible emissions by changing the content of B 2 O 3. Their optical properties, structure, and temperature-dependent emission were investigated systematically. All the Bi ions-doped glasses show broadband luminescence from 350 nm to 700 nm, the emission bands show a blue shift from 454 nm to 435 nm when the concentration of B 2 O 3 increases from 0% to 10%. The emission intensity reaches the maximum value of 5% B 2 O 3 concentration, which attributes to the number and distribution of bismuth ions luminescent centers. Furthermore, thermoluminescence is observed in this glass system. In this study, the coordination structure around the active centers of bismuth can be changed by modifying the glass network structure, promoting the research of tunable luminescence of bismuth ions-doped glass. [ABSTRACT FROM AUTHOR]

During the preparation of Bi 2 Sr 2 CaCu 2 O 8+ δ (Bi2212) superconducting thin films by sol-gel method, the complexing agent and sintering conditions can significantly influence the quality and the performance of thin film. In this study, Bi2212 thin films were prepared on single crystal SrTiO 3 (001) substrate, and the phase purity, crystallinity, surface morphology and transport properties were studied particularly with different sintering temperature and time, complexing agent and its ratio to metal ions. Due to relatively low carbon content, tartaric acid (TA) as a complexing agent improved the film quality and transport properties compared with the traditional ethylenediamine tetraacetic acid (EDTA). When the complex ratios of TA to metal ions was 1:1, Bi2212 thin films exhibited good epitaxial properties, a high Bi2212 phase purity and a low surface roughness of 12.74 nm. Simultaneously, under these preparation condition, Bi2212 superconducting thin film showed a higher T c, onset of 93.28 K. [ABSTRACT FROM AUTHOR]